Although the present invention will be described with particular reference to packaging in the form of a cover for the flywheel/clutch assembly of an engine in storage or being transported, it is to be noted that this application is merely illustrative of the present invention and is provided for the purpose of ease of understanding the scope and application of the invention and to allow clarity of expression to describe and define the invention. Thus, the protective cover is one example only of the packaging of the present invention. Other examples include covers for disc brake assemblies, brake discs, and other exposed bare metal components.
Additionally, it is to be noted that the term VCI includes within its scope materials, compounds, compositions, formulations and the like which are vapour corrosion inhibitors, which are classified as or are described as vapour corrosion inhibitors, which function like vapour corrosion inhibitors or are the same as vapour corrosion inhibitors and similar materials including precursors for and derivatives of vapour corrosion inhibitors.
Metal components or assemblies have a tendency to rust or otherwise corrode soon after manufacture or assembly such as for example during storage, transportation or the like or when in transit, particularly if the metal is not treated against rusting before it is shipped, and particularly, if the component includes one or more surfaces of bare exposed metal. One example of the metal components is the flywheel/clutch assembly of a motor vehicle or the rotor and disc brake assembly of a motor vehicle. With increasing globalisation of manufacturing in the automotive industries, it is common place for subassemblies of motor vehicles such as engines, gear boxes, back axles, and the like to be made in one location and shipped to a different location for assembly. Quite often, one component is made in one country and is shipped to other countries, sometimes on the other side of the world for assembly and manufacture into a vehicle. As an example, engines made in Australia are shipped to Europe for assembly into European cars during their manufacture. During the many months of storage and transport, the exposed metal engine components have a tendency to begin to rust or corrode, particularly when subjected to large variations in temperature, humidity and other atmospheric conditions or the like, making it necessary to remediate the component before use, or in extreme cases when rust is too advanced, to discard the assembly altogether, both of which actions are undesirable as being costly, time consuming and/or detract from the appearance and/or performance of the component or finished product.
Although previously, there have been many attempts to prevent rust developing in engine assemblies, existing methods of rust proofing have not been entirely satisfactory for one reason or another. As an example, metal parts which have one or more exposed bare metal surfaces can be painted or provided with a protective or barrier coating physically applied directly to the bare metal part to prevent the development of rust during storage or transport of the component by covering the bare metal to present a barrier to moisture. However, such a coating would need to be removed entirely from the metal part or parts before use. Again, this is costly and time consuming as well as being potentially damaging to the part. Therefore, it is not possible to merely coat the exposed metal parts to protect them. Thus, there is a need for a system of rust prevention or inhibition which does not require the exposed metal parts to be physically directly coated with a coating that requires removing before the part can be used.
It has been surprisingly discovered that using vapour corrosion inhibitors can provide effective rust protection or corrosion inhibition without having to directly apply the coating to the parts since indirect application of the VCI actives is sufficient to produce a corrosion inhibiting coating provided by the VCI compounds. Additionally, it has been discovered that the VCI actives do not need to be removed from the metal components before use as is required when using previously available barrier coatings applied directly to bare metal surfaces.
However, in order for VCI to work effectively, it has been discovered that there needs to be controlled release of the VCI compounds or actives at or within a predetermined rate or range of rates to provide continuous protection for the metal parts during the entire period of storage and transit by providing and maintaining an effective corrosion inhibiting atmosphere for the storage life of the metal parts.
Accordingly, it is the aim of the present invention to provide packaging having controlled release of at least one VCI compound or active to maintain a corrosion inhibiting atmosphere or environment within which to store metal components having exposed bare metal surfaces in order to inhibit or prevent rust or corrosion of the metal component occurring during storage and/or transport.
Not only is it possible using the present invention to effectively control the release of VCI to form a corrosion inhibiting atmosphere by incorporating the VCI active into a film or substrate, particularly a substrate that promotes the controlled release of VCIs, which is one aspect of the present invention, but also embodiments of the invention can be improved by modifying the basic form of the invention by providing a modified substrate having improved controlled release of the VCIs which is another aspect of the present invention.
It has been discovered also that the performance of the invention could be improved if the high cost of the packaging made by the present invention could be reduced by lessening the amount of VCI incorporated into the film whilst still having release of the active material to produce an effective corrosion inhibiting atmosphere since VCI actives are expensive thereby resulting in the film into which they are incorporated being expensive to make and use, particularly as the packaging made from the film is discarded after use, usually after a single use only. Surprisingly, it has now been discovered also that the present invention can be improved by using a reduced amount of VCI active if a modified form of the carrier material in which the VCI active is incorporated is used to form the packaging.
Accordingly, it is another aim of the present invention to provide packaging and a method of forming packaging that involves the use of a reduced amount of VCI to provide an effective corrosion inhibiting atmosphere for protecting bare metal objects located within the packaging against corrosion by using modified forms of the film.
Previous attempts at rust protection of packaged metal parts have relied upon the use of flexible packaging for wrapping around the metal part to be protected, such as for example, wrapping the metal part in brown paper or Kraft paper optionally containing a rust preventative to completely envelope or surround the part. The use of flexible materials such as paper sheets to wrap separate items cannot be used for all occasions or in all circumstances for a variety of reasons, such as for example, in attempting to protect built assemblies of components where wrapping is not possible because of the size, configuration or location of the assembly. One example of an assembly that it is not possible to wrap completely to exclude corrosive contaminants, moisture or the like is the clutch/flywheel assembly of a motor vehicle engine. Another example is the disc brake assembly and disc rotor of a motor vehicle. In both of these circumstances it is not possible to wrap the rear of the assembly because of the other componentry and subassemblies of the motor vehicle being located in close proximity so that there is little or no clearance between the assembly to be protected and the other assemblies which prevents the flexible material from going around and covering the rear surface of the assembly that is to be protected. Merely placing a flexible sheet over the exposed side of the metal part does not provide the required protection. Thus there is a need for an alternative way of protecting assemblies of a complex or convoluted shape attached to or located near to other subassemblies from corrosion other than wrapping in a flexible paper sheet. It has now been discovered surprisingly that instead of using flexible sheets of paper to wrap the assemblies, a rigid or semi-rigid protective cover or similar that retains its shape during use can be used to provide the corrosion protection when the rigid or semi-rigid shaped protective cover is attached to the assembly. Until the discovery of the present invention it was thought that making a shaped or semi-shaped article containing a VCI to provide protection was not possible because the VCI compound may migrate or vaporise during manufacture of the shaped article, particularly if heat and/or pressure was used to form the shaped article, so that the VCI would be prematurely exhausted from the shaped article leaving insufficient VCI to provide a Vapour Inhibiting Atmosphere for sufficient duration to provide protection for the length of time the part was to be stored. Contrary to this expectation it has now been discovered that the VCI can be retained in the article during shaping by making the article from a substrate that has a layered structure or arrangement including more than a single layer in which the VCI is incorporated primarily into one of the layers and another of the layers primarily provides the ability to form the shaped article and for it to retain its shape, preferably by moulding the shaped article to conform very closely to the exact shape of the metal part which is to be protected. Accordingly, it is one aim of the present invention to provide a rigid or semi-rigid shaped article from a substrate having two or more layers in which one layer has a VCI active so that when the article is connected or attached to the metal part a corrosion inhibiting atmosphere is formed to provide protection for the metal part.